Marx

“…in dialectics the definite contours of concepts (and the objects they represent) are dissolved. Dialectics… is a continuous process of transition from one definition into the other. In consequence a one-sided and rigid causality must be replaced by interaction. … the most vital interaction… [is] the dialectical relation between subject and object in the historical process… in all metaphysics the object remains untouched and unaltered so that thought remains contemplative and fails to become practical; while for the dialectical method the central problem is to change reality.”